1. Field of the Invention
The present invention relates to a method of manufacturing a radiological image conversion panel and also relates to a radiological image conversion panel.
2. Background of the Related Art
This kind of radiological image conversion panel is used in an indirect type (X-ray indirect conversion system) of radiation detector together with a sensor panel having a plurality of photoelectric conversion elements. This kind of radiation detector is known, e.g., in JP-A-2012-159305. The radiation detector has a phosphor layer (scintillator) made up of a group of columnar structures formed on one of surfaces of a substrate with fluorescent crystals being respectively formed in the form of columns. In this arrangement, the light generated inside each of the columnar structures through radiation exposure is caused to be propagated while being confined within the columnar structures by taking advantage of the difference between the refractive index of the columnar structures and the refractive index of the gaps (air) between the columnar structures (optical confinement effect). The light is caused to be incident on the photoelectrical conversion elements respectively disposed opposite to the columnar structures. The light is thus converted into electrical signals (image signals) depending on the amount of light.
If the light generated in the columnar structures gets leaked outside without being confined to the columnar structures, the leaked light will be incident on columnar structures other than the photoelectrical conversion elements on which the light is originally intended to be incident. The amount of light will then become insufficient in the photoelectrical conversion elements on which the light is originally intended to be incident. On the other hand, the amount of light increases in the photoelectrical conversion elements into which additional light is caused to be incident. As a result, the quality of image is deteriorated. Therefore, in order to obtain clear images in the radiation detector, it becomes important how the leaking light to the outside of the columnar structures can be suppressed.
As a solution, in the above-described conventional example, the following proposal is made. Let that side of the columnar structures which lie on the side of the substrate be defined as a base end and let that side of the columnar structures which lie on the side of the photoelectric conversion elements be defined as a front end. Then, the front end of the group of columnar structures is covered with a reflection film which is made of a metal or a metal alloy. However, if the reflection film is formed in a manner to fill the gaps between the front ends of the adjoining columnar structures, the light will be reflected only on the interface between the columnar structures and the reflection film. Further, since there is no reflection film on the side of the base end of the substrate, there is a limit in effectively suppressing the light from leaking to the outside of the columnar structures.